Non-Negotiable
by Zet Sway
Summary: "I will deal with him as soon as I'm finished making you forget every second you ever spent by his side." Thane/FShep. Implied past relationship with Kai Leng. Oneshot.


Warning for sortakinda dubcon, light bondage, and some iffy words used to refer to the female anatomy.

This prompt was a year in the making. I truly respect the anon who shared it with me for having the stones to stick their neck out there and ask for it. ~3,500 words, this feels like a goddamn novel in comparison to my other work.

Before we begin, please know that **the prompt for this fic was Thane punishing Shepard for a past relationship with Kai Leng**. Every Thane fan I know really hates that fucker, so I understand why someone might not want to read this kind of "what if" scenario. That's totally cool. Just hit the back button if it's not for you :)

Many thanks to my beta reader over on tumblr for trudging through my first draft with so many changes in tense and point of view and a thousand inconsistencies! thank you for supporting me! /hug :D

Mass Effect and all associated characters belong to Bioware. I make no money from this fanfiction.

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They'd gotten on the subject somehow after talking about Thane's fonder memories of his life on Kahje. She mentioned an ex-boyfriend in passing, laughing to herself about a suddenly newly-realized affinity for assassins. The conversation had taken an immediate downturn from that point. Thane was clearly concerned, and despite her efforts to change the subject, he continued to press her for information.

"Siha," he said plainly, "Surely you did not think you could keep this from me forever. This news is distressing, to say the least. You must tell me of him."

She rolled her eyes. "And if I don't?"

"Do not test me, Shepard."

She grumbled to herself before she stood abruptly and left the table, content to leave him without another word, given the way he acted as if her past was his property.

He reacted instantly. A wave of crackling energy slammed her into the opposite wall and she gasped in surprise. "What the fuck's gotten into you?"

He stood before her, pressing an arm over her throat. "I will ask you again. What was his name?"

She wanted to scream her anger and frustration. This was a side of Thane she had never seen – dangerous, uncalled for, and above all, rude. She scoffed. "It's none of your damn business, Krios. Leave it alone."

His eyes narrowed. Inches away from her face, his breath rolled hot over her skin. "Regardless of what you may think, your past relationship with another assassin is my business for a multitude of reasons. You will tell me what I want to know."

"I don't have to tell you shit," she sneered. His arm pressed further into her throat. She could feel rage radiating off him like the crackling blue of his biotics.

His fingers tightened on her throat and when she met his eyes they were as black as the space between stars. A low growl emanated from him – a sound that she felt rather than heard - and she knew in the back of her mind that it was just an intimidation tactic, but that didn't stop the smallest inklings of fear from stirring at the back of her mind.

He pressed his full weight against her and broke their standoff with a kiss that was a punishment in its own right. His hand grasped her hip, traveling up her side and pausing beneath her breast. She nearly laughed. Leave it to Thane to sexualize an argument born of anger and jealousy. Her fear was banished instantly. If this was the game he wanted to play, she would push him as far as he was willing.

She challenged him with defiance in her eyes even as her heart pounded in her chest. At this close proximity, there was no way he didn't sense her adrenaline. His strength was incredible. Arousal stirred within her and she relished in the feeling, a small sound escaping her throat.

Thane didn't miss a beat. As though he read her mind, he relaxed, keeping a hand at her throat to assert his dominance as he leaned in, lips brushing her ear.

"Are you enjoying this, Siha?"

She snorted but said nothing, trying her damnedest not to show it when her body heated at his words.

"Tell me what he was like," he whispered. His hand slid over her hip and gripped her almost painfully, pulling her tight against him. "Was he human? Powerful? Attractve?" The increasingly lower tones in his voice set her nerves on fire.

"It's none of your business," she hissed, and the fingers at her throat twitched.

"Don't pretend you don't know I can feel your arousal. Did he make your body burn like this? Are you thinking of him?" His head dipped to her neck and she felt chills as he dragged blunt teeth over her pulse.

"The only reason I'm thinking of him is because you brought him up."

Without warning, he pulled her from the wall and spun her around, pressing the now obvious bulge in his pants against her backside as he pushed her into the wall. "You're right, Shepard. But one way or another, I will make you talk."

Shepard ground her ass into his hips with a smile. "Make it worth my while and I'll tell you everything you want to know."

-

He lead her up to the captain's cabin and she stood silently at the foot of the stairs, arms crossed over her chest, leaning her weight on one leg. From beneath her bed, he produced a box – her own personal toybox - and her heart beat that much faster with the thought of all the exciting directions Thane's intellect was bound to take this.

He selected a length of rope and turned to her, pulling her camisole up and bunching it over her breasts. Deft fingers ghosted over the edge of her bra and flicked at the clasp between her breasts, leaving it to hang loosely off her shoulders as he circled behind her.

His voice was a breathy whisper at her ear as he drew her wrists together. "Perhaps you think me selfish for demanding such direct answers about your personal history, but I have already been more than forthcoming with you about my past. You cannot keep this information from me." He looped the rope first around her wrists and worked his way up around her upper arms, forcing her elbows together and her shoulders back. "So tell me, what was his name?" He finished the statement with a sharp tug on the knot, securing her restraints.

She eyed him, tight-lipped and cocky. Her state of partial undress left her looking that much more put up for show, and her defiant posture only emphasized that point. He watched her for a moment and she said nothing, worrying her lower lip with her teeth and tightening her thighs with anticipation.

He sat on the edge of the bed, shrugging out of his jacket and leaving on the mattress behind him. "Come here," he said finally, and she did. He shifted her, spinning her around, and carefully, he lifted her left leg and bent it at the knee, pulling it back to rest alongside his thigh. She took the hint and allowed him to position her on his lap, bound wrists forcing her hands to cover his erection. She massaged him through his pants.

Shepard didn't need to look to see his hands light up with a weak biotic glow – they pulsed against her belly as he smoothed them up her torso to cup her breasts. She moaned at the power humming through his fingertips as he gently rolled and pinched her nipples, but his touch was featherlight. She squirmed in his lap, unable to get any friction against the burning need between her legs. Massaging the bulge in his pants, she ran her open palm firmly over his cock and searched for a zipper she couldn't seem to find. Her touch seemed to have little effect on him, however, and bound as she was, there was little she could do as he continued to touch her, scaled palms and humming biotics slowly but surely working her into a needy mess of sexual desire.

She gasped sharply when his power suddenly intensified, a blue spark leaving the tip of his thumb as he dragged it slowly over one nipple. The sensation was a wire of pure pain and pleasure that shot straight to her clit, boiling her blood and jolting her into a state of irrefutable arousal. She writhed, pushing her chest into his hands in hopes he would continue. Another spark, this time on the underside of her breasts, and again between them, each one cracking sharply in their quiet bedroom. Shepard whimpered in his arms as he peppered her torso, up her sides and over her collarbone and down her shoulders and back to her breasts again, where he shocked her nipples in tandem and she wailed with pleasure, eyes shut tight.

Her head fell back on his shoulder as he continued, drawing his hands down her belly and between her legs. He rubbed her firmly through her pants, free hand gripping her hip to hold her firmly in his lap as he seemed to lose himself to her body. For a moment, she thought his lust had won – his breath whispered past her ear in quiet pants as his hips rocked slowly against her hand and he groped her in earnest, fingertips pushing into her cleft despite the resistance of her clothing. Shepard gasped through clenched teeth, letting her weight fall on him to leverage her hands against his cock and force herself against his hand, but true to his nature, he anticipated her move as soon as she tensed her shoulders. She sagged as he withdrew his hand and replaced it against her throat.

A low sound came from his throat, a growl that seemed to shoot down her spine from where he pressed his lips to her neck. The feeling gathered between her legs and she fought to suppress her whine of frustration.

"I won't give you an ultimatum, Shepard," he said, his voice low. "But there is no honor among assassins." His hands smoothed down over her breasts and further still to her inner thighs, where he gripped her firmly as he continued. "If this man from your romantic history is a rival assassin, it will cause problems for both of us."

Her hips rolled against his chaste touch and she sighed with frustration. "We aren't even in touch anymore."

He squeezed her thighs, bowed his head to her shoulder. "I need to know for sure."

She gasped when she felt his teeth rake over her skin in an open-mouthed kiss. "My word isn't enough?"

"No," he said firmly, hauling her closer against him with sudden force and she yelped in surprise. "This isn't negotiable, Commander."

"You're that jealous?" she choked out with defiance.

"I have no patience for this," he hissed against her ear. "This issue of your last assassin boyfriend is more important than your pride or your ego. Tell me his name."

Shepard's laugh was dry and sarcastic despite Thane's now painful grip on her thighs. His fingers dug into her flesh as he forced her further open. His unusual display of aggression turned her on beyond imagining but she forced herself to consider his words as his tone increased in severity. Pride? Ego? For sure, she was not lacking in those areas, but she cared little about her personal pride at this exact moment, bound and held against him as he teased her, impassively. What if she did tell him? Would he reward her? Worse yet, would he stop?

"And what if he is a rival? What then?" His lips and teeth tugged on her earlobe. Shepard fought to ignore the sensation for just a few seconds longer.

"I will deal with him as soon as I'm finished making you forget every second you ever spent by his side."

Silence fell as he withdrew his hands and sat back, leaving her to balance herself without his warmth.

Shepard sighed. "I met him by chance when I visited Alliance command back on Earth. His name was..." She sighed. Thane said nothing. "His name was Kai Leng. He was an assassin working for the Alliance."

It was Thane's turn to laugh, apparently, as he rewarded her by pressing himself against her again. "Leng?" he said as he worked to unclasp her pants. With an arm around her belly, he leaned them back against the bed together so she lay flat against his chest, thighs burning with the stretch. "You could have done so much better, Siha."

She barely heard him, moaning as he slid one hand beneath her panties to finally touch her where she burned the hottest. He his fingers slid easily against her arousal, rubbing wide circles over her sex.

"Are you going to tell me you didn't know Leng was working for Cerberus now?" He brought another hand over her breast and she tensed with anticipation as she felt the hum of his biotics newly flickering across her aching flesh.

"I may have caught wind of it."

"Am I to assume this is an innocent coincidence?"

His fused fingers dipped into her cunt for a scant moment and she moaned. "Considering the circumstances of my 'alliance' with Cerberus?"

"You have a fair point," he said, and she almost sighed with relief until he popped a biotic spark against her sex. "But Leng deliberately targets non-humans." Another weak spark flicked down her lips and she gasped, grinding against his hand. "You can imagine that this might cause some problems for me."

"Nothing you can't handle, I'm sure," she managed. "You must have known about his allegiance with Cerberus before you decided to-" her voice broke as he drove his fingers into her. "-before you volunteered for the mission."

He tucked his arm around her again and rolled them both over until she was flat on her belly. She groaned in frustrated arousal.

"Naturally," he said as he rose from the bed and began pulling her pants down her legs. He hauled her back toward him until her hips sat on the edge of the bed and bent her calves into the air as he spread her knees. "But there were more important matters at hand. I had little concern for him until now."

She moaned as he abruptly pushed his fused fingers inside her slick channel, turning his hand down to wedge his thumb against her clit. The sensation was pure bliss, for the three seconds it lasted. She felt the familiar hum of biotic energy, the only warning she got before he withdrew and flicked a spark of energy straight across her clit. She reeled, shocks of searing pain and pleasure echoing through every nerve in her body.

"You will never speak to him again," Thane continued as he produced another length of rope and looped it around the binds on her wrists, letting the ends fall loosely in equal lengths at her sides. He rolled her again onto her back. "You may never speak of him again." Her knees were pushed back, and he used the tails of the rope to hold them there, fastening them to her bound hands as closely as her body would allow, forcing her open and spreading her wide. Her body burned with the stretch and she groaned, delirious with need.

As a final touch, he pushed a pillow beneath her head so she could watch as he began, finally, to disrobe. Shepard watched with rapt anticipation, seconds stretching into hours as he pulled his shirt over his head before letting his hands fall to the waistband of his pants to unfasten them and drag them down his hips. She moaned quietly.

"Should you be asked to liaise with him for Cerberus operations, you will allow me to accompany you and handle communications at all times," he continued. She hardly heard him, eyes transfixed on his hands as he stroked his arousal slowly, fingertips tracing the subtle ridges on his shaft.

She scoffed, defiant as she could be with her legs forced open and her body on display for a man she lusted for more than any other. "I don't need your permission, Thane, and I certainly don't need a babysitter."

"That's not for you to decide."

Pissed off as she was, his orders turned her on immensely. "You think that somehow, since I dated a rival assassin of yours, you're going to tell me what to do on my ship?"

He grabbed her knees and forced her into an awkward and painful sitting position, supporting her with his body as he knelt to meet her face to face, one hand sliding around her throat. "That's exactly what I think, Siha."

He dropped a biotically charged hand between her legs and traced the folds of her soaked cunt. Her eyes fell closed as he teased her entrance, slicking his fingertips to rub them in the lightest, most exquisite circles over her aching clit. She felt like she could scream, pent up pressure in her body making her squirm fruitlessly for more, just the tiniest bit more of that humming, featherlight touch to tip her over the edge as her mouth searched for his lips, so close to hers. He obliged, fingers around her throat pulling her closer in order to meet her kiss, her profound groan of frustration lost to his greedy mouth when he pulled his hand away and left it to linger inches away from her sex.

She felt the heat from those fingers, the faintest vibrations of his biotic energy increasing in power with every second, and that was it – she'd had enough – opened her mouth to tell him off but he pushed his tongue between her lips and released his charge with a crack that flicked over her clit in a flash of blue and set her body alight. She went limp and her mind blanked for one fragile second as a strangled cry left her throat - the sensation was indescribable, pain and pleasure fusing together like sand after lightning strike. Thoughts fled her mind and he released her, throwing her back against the bed.

"That's exactly what I think," he repeated. "And after tonight, I have no doubt you will oblige me."

It was hard to remember what he was even talking about as he leaned over her, cock sliding against her pussy as he met mouth with his lips and raised his charged hands to her breasts. His venom swam in her veins, clouding her thoughts and heightening every sensation and she dimly realized he had intended for this, saved his kiss for this moment to make her that much more vulnerable. Without a doubt, it had the desired effect. Shocks of energy cracked across her nipples as the head of his cock and the ridges along his shaft slid over her clit and she moaned incoherently. He handled her roughly now, thrusting against her, fingertips roaming her body and popping sparks of sensation against every inch of skin he could reach, down her chest, across her belly, against her inner thighs before he finally arrived right where she wanted him. He forced his fused fingers roughly into her channel and curled them up, pressing harder, focusing his energy and releasing it over and over as he fucked her with his hand, thumb shocking her clit in tandem. She screamed, bucking wildly against him as seconds blurred into hours and her orgasm was ripped from her like a white hot splinter. Her head swam with the aftershocks coursing over and under her skin.

He allowed her no rest, withdrawing his hand and guiding himself into her throbbing, over-sensitized cunt. Strong hands held her hips in a bruising grip that would without a doubt leave a rash by the morning, but she couldn't find it in her to care. She would give him whatever he wanted – no amount of pride was worth losing this – his guttural moans as he pounded her into the bed and the blinding pleasure of it, watching every inch of him disappear into her as she stretched to accommodate every inch and every ridge and oh, oh, oh-

It was over far too soon. Her body went lax in her restraints as the world came to. After a few tired moments, he lifted himself from her and began untying her ropes with shaky hands. As she collected her thoughts, she didn't know what to say.

After the show he made of tearing her authority to shreds, he was gentle with her. She stretched her aching shoulders as the ropes came free and he soothed her reddened skin with soft kisses.

"I shouldn't have treated you so harshly," he said, breaking the silence.

"Talk to me like that again and you'll have another thing coming," she laughed softly. "The sex, however..."

"Mmm," he agreed, pulling her bunched up shirt over her head. He led her to the shower, setting the fans high and the water warm to wash his oils from her skin.

Later that night, as they curled together in their bed, hovering on the twilight precipice of sleep, he spoke.  
"I will kill him, Siha."

One arm protectively around her, he seemed almost like a jealous child.

"I will kill him."

She knew he meant every word.

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Thank you for reading!


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